THE  HYDROLYSIS  OF  SUCROSE  BY  THE 
GASTRIC  JUICE 

BY 


ROBERT  McCLAUGHRY  HILL 
B.  S.,  Carthage  College, 
1915 


THESIS 


Submitted  in  Partial  Fulfillment  of  the  Requirements  for  the 


Degree  of 

MASTER  OF  SCIENCE 
IN  CHEMISTRY 


IN 

THE  GRADUATE  SCHOOL 

OF  THE 

UNIVERSITY  OF  ILLINOIS 


1921 


Digitized  by  the  Internet  Archive 
in  2015 


https://archive.org/details/hydrolysisofsucrOOhill 


YVs*^ 

UNIVERSITY  OF  ILLINOIS 


THE  GRADUATE  SCHOOL 


Hay 24, I92l_ 

I HEREBY  RECOMMEND  THAT  THE  THESIS  PREPARED  UNDER  MY 
SUPERVI SION  BY Robert  McQlaughry  Hi 1JL 

ENTITLED The  Rvdrolysis  of  Sucrose  by  the  Gastric  juloe» 


BE  ACCEPTED  AS  FULFILLING  THIS  PART  OF  THE  REQUIREMENTS  FOR 


THE  DEGREE  OF 


Master  of  Scienoe 


In  Charge  of  Thesis 


Head  of  Department 


Recommendation  concurred  in 


Committee 


on 


Final  Examination* 


*Required  for  doctor’s  degree  but  not  for  master’s 


4 


o <rj> 

c'C 


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V-  ' 


* ■ • 


INDEX 


Page 


I. 

Introduction . 

1 

II. 

Methods. 

5 

III. 

The  Action 
on  Sucrose 

of 

in 

Hydrochloric  Acid 
Vitro. 

6 

IV. 

The  Action 
on  Sucrose 

of 

in 

Gastric  Juice 
Vivo. 

7 

V. 

The  Action 
on  Sucrose 

of 

in 

Gastric  Juice 
Vitro. 

10 

VI. 

The  Retention  of  Glucose  and 
Sucrose  in  the  Stomach. 

12 

VII. 

Summary. 

14 

Bibliography. 

15 

Tables. 

17 

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I,  Introduction. 


The  question  of  the  opportunity  for  and  extent 
of  hydrolysis  of  cane  sugar  in  the  stomach  normally  is 
still  an  open  one.  While  it  is  generally  conceded  that  the 
acidity  of  the  gastric  juice  is  sufficiently  high  to  permit 
of  a considerable  degree  of  hydrolysis  over  a prolonged  per- 
iod of  time,  the  actual  extent  to  which  this  acid  hydrolysis 
may  proceed  under  normal  conditions  of  diet  in  man  has 
never  been  the  subject  of  careful  experimental  study.  Such 
a study  has  been  attempted  in  the  present  instance. 

Robner  (l)  in  1859  and  Claude  Bernard  (2)  stated 
that  gastric  juice  had  the  power  of  inverting  cane  sugar. 
Experiments  carried  out  by  Hoppe-Seyler  (3)  in  1856  and 

n . . 

Kuiz  (4)  1874  indicate  that  the  gastric  juice  has  no  such 
power  when  the  sugar  is  fed  in  moderate  quantities.  Hoppe — 
Seyler,  however,  found  appreciable  inversion  when  large 
quantities  of  sugar  were  fed.  In  1887  Seegan  (5)  carried 
out  sugar  feeding  experiments  on  dogs.  The  dog9  were  fed 
100  g.  of  cane  sugar  daily  for  from  7 to  8 days  and  at  the 
end  of  that  period  were  killed  and  examinations  made  of  the 
contents  of  the  stomach  and  duodenum.  Since  glucose  was 
found  in  the  stomach  and  no  sucrose  was  found  in  the  duo- 
denum, Seegan  came  to  the  conclusion  that  sucrose  is  com- 
pletely inverted  in  the  stomach.  Three  years  later,  Voit 
(6)  carried  out  very  similar  experiments  with  rabbits,  to 
which  were  administered  30  g.  of  suorose.  Six  and  a half 


. 


' 

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; 


, 


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3 


hours  later  they  were  killed  and  examinations  made  of  the 
different  portions  of  the  alimentary  tract.  Analysis  showed 
that  of  the  3Ugar  remaining  in  the  stomach  90$  was  hydrolyz- 
ed and  only  3 mg.  of  sucrose  in  the  duodenum,  an  amount 
thought  to  he  within  the  experimental  error  of  the  methods 
employed.  The  conclusion  drawn  wa3  the  same  as  that  of 
Seegan,  that  inversion  was  practically  completed  in  the 
stomach.  Voit  was  able,  however,  to  recover  from  the  entire 
alimentary  tract  only  16$  of  the  sucrose  fed.  In  consider- 
ation of  this  fact  and  of  the  short  time  that  carbohydrates 
are  now  known  to  remain  in  the  stomach,  it  seems  that  the 
evidence  on  which  the  conclusion  is  based  is  insufficient. 

In  1898  Ferris  and  Lusk  (7)  carried  out  a series  of  hydrolysis 
experiments,  in  vitro,  with  1$  to  5$  of  sucrose  solutions  to 
see  whether  the  normal  gastric  concentration  of  hydrochloric 
acid  (0.3-0, 3$)  was  sufficient  to  account  for  the  inversion 
found  in  Voit* 3 experiments.  While  the  inversion  in  6.5 
hours  wa3  10$  to  30$  lower  than  that  found  by  Voit  in  rab- 
bits, they  concluded  that  the  inversion  in  the  stomach  could 
be  completely  accounted  for  by  the  concentration  of  free 
acid.  In  1902  Widdicombe  (8)  reported  the  presence  of  an 
active  sucrase  in  the  gastric  juice  of  dogs  and  pigs,  but 
Lusk  (9)  in  1904  repeated  these  experiments  and  was  unable 
to  corroborate  his  findings. 

In  regard  to  the  action  of  gastric  juice  on  sucrose 
the  statements  in  the  current  textbooks  are  very  contradictory. 
Some  of  the  authors  recognize  the  unsettled  state  of  the 


Jl 


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question  but  others  make  positive  statements,  - hardly  just- 
ified by  our  present  knowledge  - the  contradictory  nature  of 
which  has  given  rise  to  considerable  confusion.  The  follow- 
ing quotations  illustrate  the  widely  varying  treatment  of  the 
subject:  " — the  hydrolysis  of  the  carbohydrates  of  the  food 
may  be  continued,  to  some  extent  at  least,  by  the  hydrochloric 
acid  of  the  stomach.  This  chemical  hydrolysis,  however,  if 
it  occurs,  is  of  less  importance  than  the  action  of  the  gastric 
enzymes  upon  proteins,  milk  and  fats.”  (Bainbridge  and  Menzies 
(10)).  "While  proteids  are  practically  the  only  nutrients 
digested  in  the  stomach,  it  is  also  true  that  none  of  the 

preparatory  actions  on  other  nutrients  take  place  here. 

Sugar  and  certain  salts  may  also  be  dissolved  here  by  the 
water  and  acid  of  the  gastric  juice."  (Eddy  (11)).  "Gastric 
juice  has  no  direct  action  on  carbohydrates."  (Huxley  (is)). 

In  contrast  to  these  we  have  --"By  the  action  of  the  hydro- 
chloric acid  (of  the  gastric  juice)  certain  changes  are  in- 
duced in  the  food  stuffs.  Cane  sugar  is  inverted  to  glucose 
and  fructose."  (Starling  (13)).  "It  (gastric  juice)  inverts 
cans  sugar  into  glucose  and  fructose."  (Halliburton  (14)). 
According  to  Mathews  (15)  "To  what  extent  cane  sugar  is  in- 
verted in  the  stomach  will  depend  on  the  length  of  time  it 
remains  there  after  free  acid  appears.  This  time  is  normally 
so  short  that  probably  little  inversion  occurs, " and  Hammer- 
sten  (IS)  "The  statements  in  regard  to  the  ability  of  gastric 
juice  to  invert  cane  sugar  are  very  contradictory.  At  least 


. 


this  action  of  the  gastric  juice  is  not  constant,  and  if  it  is 
present  at  all  it  is  probably  due  to  the  action  of  acid. " 

Those  who  have  held  that  the  hydrochloric  acid  of 
the  gastric  juice  was  the  active  agent  in  the  hydrolysis  of 
sucrose  in  the  stomach  have  based  their  belief  on  experiments 
carried  out  in  vitro  with  sucrose  in  acid  solutions  of  the 
strength  assumed  to  be  present  in  the  stomach.  Based  on  this 
assumption  the  inversion  could  not  be  very  great  if  the  3hort 
time  that  sucrose  remains  in  the  stomach  under  normal  conditions 
is  considered.  Those  who  have  believed  that  there  are  other 
factors  concerned  have  argued  that  on  postmortem  examinations 
after  sucrose  feeding,  sucrose  and  reducing  sugar  are  found 
in  the  stomach  whereas  only  invert  sugar  is  found  in  the 
duodenum.  Thi3  seemed  to  prove  that  the  sucrose  was  all  hydro- 
lyzed before  it  passed  the  pylorus. 

All  of  our  knowledge  of  the  extent  of  inversion  of 
sucrose  in  the  stomach  has  been  obtained  from  hydrolysis  by 
hydrochloric  acid  in  vitro  and  from  postmortem  examinations 
after  sucrose  feeding.  At  best  the  results  of  such  postmortem 
examinations  are  very  doubtful  indices  of  the  actual  physio- 
logical processes  under  normal  conditions.  For  these  reasons 
it  was  thought  that  it  would  be  profitable  to  carry  out  a 
series  of  direct  experiments  on  the  inversion  of  sucrose  in 

the  human  stomach.  The  Rehfuss  stomach  tube  makes  such  an 

» ?* 

examination  especially  feasible,  not  only  because  the  exam- 
ination is  made  under  normal  conditions  of  digestion,  but 
because  it  is  possible  to  follow  the  course  of  the  inversion 
by  making  use  of  the  "fractional"  method  of  analysis. 


= 

- 5 - 

II.  Methods. 

The  Benedict -Osterberg  (17)  modification  of  the 
Benedict  blood  sugar  method  was  used  for  the  determination  of 
the  glucose  in  these  experiments.  The  picric  acid  employed 
was  purified  according  to  the  procedure  of  Folin  and  Doisy  (18). 
Picramic  acid  purified  by  the  method  of  Egerer  (19)  was  used 
as  the  color  standard.  The  sucrose  used  in  these  experiments 
was  purified  from  the  best  commercial  granulated  sugar.  The 
method  of  purification  wa3  the  following:  A thick  syrup  was 

made  by  dissolving  the  sugar  in  water  which,  to  avoid  any 
hydrolysis,  was  not  heated.  The  syrup  wa3  then  poured  slowly 
into  95 $ alcohol  from  which  sucrose  precipitated  out  in  very 
fine  crystals.  A second  precipitation  was  made  and  the  sugar 
then  dried  with  suction  on  a Buchner  funnel  and  finally  in  a 
vacuum  desiccator.  The  sucrose  purified  in  this  way  which  we 
used  in  our  experiments  when  tested  in  the  polar imeter  showed 
a purity  of  99.98$. 

The  possibility  was  suggested  that  the  picrate- 
picric  acid  reagent  might  invert  some  of  the  sucrose  and  thus 
cause  high  results.  To  test  this,  known  amounts  of  sucrose 
were  added  to  a standard  solution  of  glucose  containing  one 
mg.  of  glucose  in  4.0  cc.  The  glucose  was  then  determined 
in  the  solutions  made  up  in  the  same  way.  The  results  given  in 
Table  I show  that  the  glucose  content  is  not  altered  by  the 
presence  of  sucrose  and  that  the  picrate-picric  acid  reagent 
does  not  invert  any  of  the  sucrose  present. 


. 


* 


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, 


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, . 


. 


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- 6 - 

III.  The  Action  of  Hydrochloric  Acid 
on  Sucrose  in  Vitro. 

In  order  to  determine  to  what  extent  hydrochloric 
acid  in  the  concentrations  found  in  gastric  juice  would  invert 
sucrose,  hydrolysis  experiments  in  vitro  were  run.  Ferris  and 
Lusk  (7)  have  carried  out  such  determinations.  We  repeated 
these  experiments  using  essentially  the  same  procedure,  the 
details  of  which  are  indicated  in  Table  II.  Erlenmeyer  flasks 
containing  2Q.0  cc,  of  0.5 $ and  1.0$  sucrose  solution  with 
the  desired  hydrochloric  acid  concentration  were  incubated  for 
two  hours  at  37°  C.  and  samples  withdrawn  at  stated  intervals 
for  analysis.  The  samples  were  immediately  neutralized  exactly 
to  methyl  red-methyl  blue,  made  up  to  definite  volume,  and 
the  glucose  determined  in  aliquots.  The  results  of  these  analyses 
are  shown  in  Table  II.  Our  figures  agree  in  general  with  the 
results  of  similar  experiments  of  Ferris  and  Lusk  (7),  following, 
as  they  point  out,  Wilhelmy* s law  of  chemical  change.  As  the 
action  of  the  acid  continues,  the  concentration  of  the  sucrose 
decreases  so  that  the  rate  of  the  reaction  becomes  les3  a3  it 
proceeds.  In  the  case  of  the  1.0$  sucrose  in  0.7$  hydrochloric 
acid  if  the  rats  of  the  reaction  remained  the  same  the  inversion 
would  be  8,4$  at  the  end  of  one  hour  and  IS. 8$  at  the  end  of 
two.  Actually  the  inversion  at  the  end  of  these  periods  is 
8.3$  and  15.3$  showing  the  progressive  decrease  in  the  rate  of 
inversion. 


, 


. 

1 


- 

. 

► 

. 

■ 


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— - -- 


7 


IV.  The  Action  of  Gastric  Juice  on  Sucrose 

in  Vivo. 

The  general  procedure  used  by  Okey  (30)  in  her  invest- 
igation of  the  hydrolysis  of  inulin  in  the  stomach  wa3  followed 
in  these  experiments.  The  subjects  were  healthy  men  and  women, 
students  in  the  laboratory.  The  experiments  were  carried  out 
on  the  fasting  subject,  no  food  having  been  consumed  since  the 
evening  meal  of  the  previous  day.  In  the  earlier  experiments 
a "meal”  was  given  consisting  of  the  whites  of  three  eggs 
cooked  "soft".  As  an  experiment  (Table  III)  carried  out  with 
the  egg  white  meal  without  sucrose  showed  that  the  egg  white 
contained  an  appreciable  amount  of  glucose,  for  which  corrections 
had  to  be  made,  in  the  later  experiments  50  g.  of  cottage 
cheese  were  used  as  the  test  meal.  The  cottage  cheese  was 
repeatedly  triturated  with  water  (7-10  times)  and  drained 
through  cheesecloth  until  5 cc.  of  the  wash  water  gave  no 
appreciable  reduction  with  10  cc.  of  Fehling* s Solution.  About 
fifteen  minutes  after  the  meal  was  eaten  the  stomach  tube  was 
taken,  and  after  five  minutes  5.0  g.  of  sucrose  in  150  cc.  of 
distilled  water  were  given  through  the  tube  and  the  tube  rinsed 
with  50  cc.  of  distilled  water.  In  the  later  experiments  lOOcc. 
of  the  distilled  water  were  given  before  the  sucrose  and  after 
five  minutes  a sample  withdrawn  to  test  for  reducing  substances. 
After  the  introduction  of  the  sugar,  three  samples  were  removed 
at  twenty  minute  intervals  for  examination.  The  "free"  and 
"total"  acid  were  titrated  against  standard  sodium  hydroxide 
using  diraethylaminoazobenzene  and  phenolphthalein  as  indicators. 


. 

. 


• . 

. 


■ 

, 

' 

• 

- 

. 

. 

An  aliquot  was  neutralized,  immediately  and  the  protein  precip- 
itated by  adding  the  picrate-picric  acid  reagent  with  which 
it  was  made  to  25  cc.  The  glucose  was  then  determined  by  the 
Benedict -Osterberg  modification  of  the  Benedict  method.  These 
results  represent  the  amount  of  reducing  sugar  present  due  to 
the  normal  action  of  the  gastric  juice.  A second  aliquot  was 
incubated  at  37°  C.  for  two  hours  and  the  reducing  sugar  deter- 
mined in  the  same  way.  The  results  in  this  case  showed  the 
amount  of  inversion  possible  if  the  normal  gastric  juice 
were  afforded  the  opportunity  for  prolonged  action  on  the  suc- 
rose. To  a third  portion  hydrochloric  acid  was  added  to  give 
a final  concentration  of  1.0 °]o  hydrochloric  acid  and  the  mix- 
ture was  hydrolyzed  by  boiling  for  one  hour.  The  boiling  in 
acid  solution  should  completely  invert  the  sucrose  and  the 
subsequent  determination  of  the  reducing  sugar  would  then  show 
the  total  carbohydrate,  sucrose  plus  invert  sugar,  present. 
Since  regurgitation  from  the  intestine,  at  intervals,  is  now 
known  to  accompany  gastric  digestion  normally,  it  was  thought 
that  the  sucrase  of  the  intestinal  juice  might  have  an  appreci- 
able effect  in  inverting  sucrose  in  the  stomach.  To  test 
this  a sample  was  withdrawn  from  the  stomach  before  the  sucrose 
was  introduced,  and  neutralized.  Sucrose  was  added  and  the 
mixture  incubated  for  two  hours.  Any  hydrolysis  in  this  test 
would  indicate  the  presence  of  sucrase  since  other  hydrolyzing 
factors  were  eliminated.  In  none  of  these  was  there  any 
hydrolysis,  showing  the  absence  of  active  sucrase. 


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- 9 - 

Five  experiments  were  carried  out  with  the  egg-white 
meal  and  three  with  the  cottage  cheese.  In  all  seven  subjects 
were  studied.  Early  in  the  experiments  where  the  egg-white 
meal  was  ingested  (Table  IV)  there  is  apparently  a considerable 
hydrolysis  which  the  free  acid  present  cannot  completely 
account  for.  However,  when  these  figures  are  corrected  for  the 
glucose  content  of  the  egg-white  (Table  III)  the  hydrolysis 
represented  by  the  corrected  figure  can  be  easily  accounted 
for  by  the  free  acid  concentration.  This  corrected  figure  also 
correspond  very  closely  to  that  obtained  with  the  cottage 
cheese  meal  which  contained  only  a negligable  amount  of  glucose. 
After  two  hours  incubation  there  is  obtained  a hydrolysis  closely 
parallel  with  the  hydrolysis  due  to  hydrochloric  acid  alone 
in  similar  concentrations  as  shown  in  the  experiments  recorded 
in  Table  II,  The  total  sugar  present,  as  shown  by  the  com- 
pletely hydrolyzed  samples,  indicates  that  the  sugar  has 
almost  completely  left  the  stomach  at  the  end  of  one  hour.  Even 
though  the  per  cent  of  hydrolysis  is  comparatively  large,  it  is 
in  reality  of  little  consequence  because  of  the  small  quantity 
of  sugar  remaining  in  the  stomach  at  that  time. 

These  experiments  show  a slight  hydrolysis  of  the 
sucrose  in  the  sample  taken  from  the  stomach  twenty  minutes 
after  ingestion  and  a small  increase  in  the  hydrolysis  in  the 
samples  taken  later.  The  extent  of  hydrolysis  in  the  stomach 
can  be  of  no  practical  importance  because  of  the  short  time 
the  sugar  remains  there  and  in  every  case  it  can  be  almost 
completely  accounted  for  by  the  action  of  the  free  acid  present. 


' 


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• 

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- 10  - 


V.  The  Action  of  Gastric  Juice  on  Sucrose 

in  Vitro. 

To  confirm  our  findings  in  the  feeding  experiments 
a series  of  tests  were  carried  out  on  the  action  of  gastric 
juice  on  sucrose  in  vitro.  The  egg-white  meal  was  fed  in  all  of 
these  and  only  one  sample  of  gastric  juice  was  withdrawn.  This 
was  removed  40  minutes  after  the  meal  which  is  the  average  time 
of  maximum  acidity  under  the  conditions  of  these  experiments. 

In  one  portion  the  acidity  of  the  gastric  juice  was  determined, 
in  a second  reducing  sugar  was  analyzed  for.  The  latter  figure 
shows  the  amount  of  glucose  in  the  gastric  contents  and  was 
used  as  a correction  to  he  applied  in  the  following  inversion 
tests.  To  each  of  four  10  cc.  aliquots  50  mg.  of  sucrose  were 
added.  The  first  portion  was  incubated  two  hours.  This  is 
comparable  with  the  similar  tests  in  the  feeding  experiments, 
and  gave  similar  results  as  may  be  seen  by  comparing  the  fig- 
ures obtained  with  the  incubated  samples  in  Tables  IV,  and  V. 
Since  the  attempt,  described  in  Section  IV, , to  demonstrate 
the  activity  of  regurgitated  intestinal  sucrase  in  the  stomach 
did  not  give  positive  results,  a further  test  was  made.  For 
this  purpose  the  second  portion  of  gastric  juice  was  heated  to 
boiling  before  any  sucrose  was  added.  On  cooling,  50  mg.  of 
sucrose  were  added  and  it  was  then  incubated  for  two  hours.  The 
heating  would  kill  any  enzyme  that  might  be  present  and  the 
inversion  should  be  due  solely  to  the  free  acid  concent ra.t ion. 
The  third  aliquot  was  not  heated  but  was  neutralized  before  the 
addition  of  the  sucrose  and  then  incubated.  If  any  inversion 


. 


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> 

* 

. . 1 - 


> 


■»  - 


-11- 

occurred  in  this  case  it  would  necessarily  be  due  to  factors 
other  than  the  acidity  and  would  indicate  the  presence  of  en- 
zymes. The  fourth  aliquot  was  both  boiled  and  neutralized 
before  the  sucrose  was  added.  This  was  run  as  a control  and  no 
inversion  would  be  expected. 

Inspection  of  Table  VI.  shows  that  the  results  of  this 
series  of  experiments  bear  out  the  findings  in  the  feeding 
tests.  Boiling  the  gastric  juice  without  neutralization  has 
no  effect  on  its  power  to  invert  sucrose  while  neutralization 
alone  completely  takes  away  that  power.  This  shows  that  no 
enzyme  action  is  concerned  in  the  inversion  and  that  the  pre- 
sence of  free  acid  is  necessary  for  it  to  take  place.  Com- 
parison with  the  results  recorded  in  Table  II.  show  that  the 
inversion  is  practically  identical  with  that  in  aqueous  sol- 
utions of  the  same  hydrochloric  acid  concentration,  and  there- 
fore that  the  free  acid  concentration  of  the  gastric  juice  is 
sufficient  to  explain  all  of  the  hydrolysis. of  sucrose  that 
takes  place  in  the  stomach.  These  experiments  further  show 
that  if  any  sucrase  is  carried  into  the  stomach  by  regurgitat ion 
from  the  intestine  it  does  not  remain  active  long  enough  to 
have  any  effect  in  the  gastric  hydrolysis  of  sucrose. 


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. 


- 12  - 


VI.  The  Retention  of  Glucose  and.  Sucrose  in  the  Stomach. 

During  the  course  of  our  investigation  the  question 
arose  as  to  whether  glucose  and  sucrose  leave  the  stomach  at 
the  same  rate.  If  glucose  leaves  more  rapidly  than  sucrose 
it  is  evident  that  analysis  of  the  gastric  contents  alone  will 
give  figures  that  are  too  low  for  the  per  cent  of  inversion. 

Five  grams  of  glucose  were  given  under  the  same  conditions  as 
in  the  sucrose  experiments  and  samples  removed  at  twenty  min- 
ute intervals  were  neutralized  immediately  to  methyl  red — meth- 
ylene blue.  The  glucose  was  then  determined  as  in  the  previous 
experiments.  The  results  of  this  test  are  shown  in  Table  VII. 

In  Table  VIII  the  average  speed  of  evacuation  of  sucrose  from 
the  stomach  in  all  the  sucrose  feeding  experiments  is  compared 
with  the  speed  of  evacuation  of  glucose.  As  a basis  of  com- 
parison we  have  taken  the  analysis  of  5 cc.  aliquots  of  the 
first  sample,  withdrawn  twenty  minutes  after  the  meal  was  eaten. 
The  figures  in  the  table  show  the  percentage  of  sugar  still 
present  in  the  stomach,  after  forty  and  sixty  minutes,  comput- 
ed on  this  basis.  The  table  also  shows  the  free  acidity  of 
the  glucose  feeding  experiment  compared  with  the  average  free 
acidities  of  the  sucrose  experiments.  The  glucose  appears  to 
be  leaving  the  stomach  more  rapidly  in  the  first  period  but 
the  free  acidity  in  the  case  of  the  glucose  is  correspondingly 
higher  and  this  would  lead  us  to  expect  a more  rapid  evacuation. 
It  is  recognized  that  in  these  experiments  very  close  agree- 
ment cannot  be  expected  because  of  the  varying  extent  of  dil- 


' 


■ 

. 


- 13  - 


ution  of  the  sugar  solutions  by  the  gastric  juice,  and  further 
since  only  one  subject  was  studied  the  tendency  to  individual 
variation  must  be  considered.  However,  we  believe  that  this 
shows  clearly  that  there  is  no  material  difference  in  the  rate 
at  which  glucose  and  sucrose  leave  the  stomach  under  the 
conditions  of  our  experiment. 


- 14  - 


VII.  Summary. 


(1)  Hydrochloric  acid  of  the  strength  normally 
found  in  the  stomach  has  the  power  of  inverting  sucrose  in 
appreciable  quantities  in  from  one  to  two  hours. 

(2)  The  inversion  of  sucrose  in  the  human  stomach 
may  be  explained  solely  by  the  action  of  the  hydrochloric 
acid  present.  This  inversion  is  too  small  to  be  of  any 
consequence  in  the  short  time  that  the  sucrose  remains  in 
the  stomach. 

(3)  The  inverting  action  of  human  gastric  juice 

in  vitro  is  essentially  the  same  as  that  of  hydrochloric  acid 
solutions  of  the  3ame  concentration. 

(4)  We  were  unable  to  demonstrate  the  presence 
of  any  sucrase  of  either  gastric  or  intestinal  origin  in 
gastric  juice. 

(5)  Sucrose  and  glucose  leave  the  stomach  at 
essentially  the  3ame  ra.te. 


™ V wl:  I . ppiMfr 


15 


Bibliography. 

(I)  Robner,  discuis  de  sacher  cannae  in  tractu  cibario 
mutat ionibus,  dis3.  insug.  Breslau  1859;  cited  by 
Carl  Voit,  Zeit.  f.  Biologie,  1891,  Vol.  38,  p.  268. 

(3)  Bernard,  Claude,  Physiologie  experimental,  Paris, 

1855  Vol  II  p.  402. 

(3)  Hoppe-Seyler,  Felix,  Virch.  Arch.  1856  Vol.  10,  p. 
144. 

(4)  Killlz,  E.,  Beitr.  Z Path.  u.  Therapie  des  Diabetes 
Mellitus,  Marburg  1874,  p.  147;  cited  by  Carl  Voit, 
Zeit.  f.  Biologie,  1891,  Vol.  38,  p.  268. 

(5)  Seegan,  J. , Archio.  f.  d.  ges.  Physiol.  1887,  Vol. 
40,  p.  41. 

(S)  Voit,  Carl,  Zeitschr.  f.  Biologie,  1891,  Vol.  38, 
p.  3S8 . 

(7)  Ferris,  S.  J.  and  Lusk,  Graham,  Am.  Jour,  of  Physiol 
ogy,  1898,  Vol.  1,  p.  277. 

(8)  Widdicombe  J.  H. , Jour,  of  Physiology,  1903  Vol.  28, 
p.  175. 

(9)  Lusk,  Graham,  Proc.  of  the  Am.  Physiol.  Soc.,Am. 
Jour,  of  Physiology  1904,  Vol.  10,  p.  xxi. 

(10)  Bainbridge  and  Menzies,  Essentials  of  Physiology, 
Longmans,  Green  and  Co.  London,  1914,  p.  302. 

(II)  Eddy,  A Textbook  in  General  Physiology  and  Anatomy, 
American  Book  Company  New  York,  1907,  p.  116. 

(13)  Huxley,  Lessons  in  Elementary  Physiology,  The  Mac- 
millan Company,  New  York,  1918,  p,  248. 


- 16  - 


(13) 

(14) 

(15) 
(IS) 

(17) 

(18) 

(19) 

(30) 


Starling,  Principles  of  Human  Physiology,  Lea  and 
Febiger,  New  York,  1912,  p.  788. 

Halliburton,  Handbook  of  Physiology,  13th  Edition, 
P.  Blaki3ton’ s Son  and  Co.  Philadelphia,  1917,  p. 

513. 


Mathews,  Physiological  Chemistry,  William  Wood  and 
Company,  New  York,  1916,  p.  350. 

Hammarsten,  A Textbook  of  Physiological  Chemistry, 
John  Wiley  and  Sons,  New  York,  1913,  p.  449. 
Benedict,  S.  R.  and  Osterberg,  E.,J.  B,  C.,  1918, 
Vol.  34,  p.  195. 

Folin,  Otto  and  Doisy,  F.  A.,  J.  B.  C.,  1916,  Vol. 


28,  p.  349. 


Egerer,  Grete,  J.  B.  C., 


1918,  Vol.  35, 


Okey,  Ruth,  J,  B.  C., 


1919,  Vol.  39,  p. 


p.  565. 
149. 


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26 


Table  VIII. 

The  Rate  of  Evacuation  of  the  Stomach. 
Comparison  of  Glucose  and  Sucrose. 


Time  After 

Ingestion.  Free  Acidity  * 
cc.N/10  acid 

Per  cent  Remaining  in  Stomach 

Glucose 

Sucrose 

Glucose 

Sucrose 

20 

— 

— 

100 

100 

40 

57.2 

28.3 

46 

56 

60 

50.0 

32.0 

28 

26 

* The  amount  of  carbohydrate 

present 

at  the  end  of  twenty  rain- 

utes  is  taken  as  a basis  for  the  calculation  of  the  per  cent  of 
sugar  remaining  in  the  stomach  in  the  later  periods. 


*N 


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